Q&A: Is Custom (Wavefront) LASIK Right For You?

As a former "Top Gun" F-14 Tomcat fighter pilot and military eye
surgeon, retired U.S. Navy Capt. Steven C. Schallhorn, MD, has a unique
perspective on custom (wavefront) LASIK.

Dr. Schallhorn is an ophthalmologist
particularly interested in keen vision for fighter pilots. He
established a refractive eye surgery program at San Diego's Naval
Medical Center and was the first U.S. Department of Defense eye surgeon
to perform PRK, LASIK and phakic IOL procedures.

Until
his retirement in 2007, Dr. Schallhorn also directed and oversaw
expansion of the U.S. Navy's refractive eye surgery program to many
other locations.

Now in private practice in San Diego, Dr.
Schallhorn is the medical director for Optical Express. He is a frequent
speaker at conferences where the world's leading eye surgeons discuss
refractive surgery procedures such as LASIK.

Q: Dr. Schallhorn, could you define wavefront-guided (custom) LASIK?

A: A wavefront-guided procedure is a treatment based on all of the eye's optical aberrations. These aberrations are measured with a sophisticated device called an aberrometer

, which essentially takes a "fingerprint" of the eye.

This unique "fingerprint" is then used to correct vision in an equally sophisticated, computer-controlled laser.

Q: What is the difference between wavefront-guided LASIK and other types, such as conventional or optimized?

A: In simple terms, conventional or standard laser vision correction uses the prescription in a pair of eyeglasses as the basis to correct vision. It does a great job of reducing or eliminating the need to wear glasses or contact lenses.

On
the other hand, it can cause other types of optical aberrations,
especially spherical aberration. These other optical aberrations can
cause focusing problems and make objects blurry. In particular, a
significant amount of spherical aberration can cause visual problems
especially at night, in the form of glare and halos around lights.

The
"optimized" LASIK procedure was designed to be spherical
aberration-neutral, neither creating nor reducing it. The treatment is
still based on the refractive prescription in glasses. But it does not
measure and cannot correct other types of optical aberrations in the
eye.

The wavefront-guided procedure is much different than either
conventional or optimized. It uses a device, called an aberrometer, that
measures all the optical aberrations of the eye, including the
refractive prescription, to correct vision.

Wavefront, just like
optimized, can minimize induction of spherical aberrations. But it can
also measure and treat other higher-order aberrations. Wavefront LASIK is very precise, and the results are better.

But
it's not a matter of one procedure not being adequate or good or
effective. All these procedures greatly exceed established measures of
safety and effectiveness.

You might say that optimized LASIK was a great forward step, and wavefront-guided is a further great forward step.

A: An aberration is any optical irregularity that causes images to be blurry.

Common aberrations are nearsightedness and astigmatism. These can be corrected with glasses and are now termed "lower order" aberrations.

However, as we have come to discover, there can be other types of optical aberrations in the eye that cannot be corrected with glasses. These are collectively called "higher order" aberrations.

Prominent
among them are spherical aberrations and coma. Both can result in
blurry images that can be more apparent at night and cause halos around
lights as well as glare and double vision. The cornea and lens

can both have these aberrations.

The
wavefront device measures all the optical aberrations, lower and higher
order, and attempts to correct them. That's the beauty of wavefront.
Because of the nature of those aberrations, they may be causing
impairment of visual quality.

Q: But isn't the cost of LASIK eye surgery
for a conventional or optimized procedure much cheaper? If a person
needs only an ordinary correction, why spend more for wavefront-guided
LASIK when conventional or optimized LASIK procedures give acceptable
results, too?

A: There is no getting around the
fact that wavefront-guided LASIK uses much higher technology and is more
expensive. It would be the same as saying that a computer is higher
technology and more expensive than an abacus or slide rule. We would all
agree that a computer is well worth the extra expense.

But the
real advantage is more than just higher technology. Wavefront-guided
LASIK results in better outcomes, better visual quality — especially
when it comes to vision at night or in a dark environment, or when there
is a high visual demand. This has been demonstrated in studies.

Q: How much more expensive is wavefront-guided LASIK than other types of procedures, such as optimized?

A: It depends on the practice, but the difference usually is several hundred dollars more per eye.

Q: Would anyone who qualifies for LASIK be considered a candidate for a wavefront-guided procedure?

A:
Some patients are not good candidates for wavefront-guided treatment,
because it requires a very precise measurement with an aberrometer. If
the aberrometer cannot make a very precise measurement of the eye, then
the patient should not have wavefront-guided LASIK.

Examples would be if the patient had a scar on the cornea or if the patient was younger and could not relax accommodation

(focusing ability) enough for a precise measurement.

Also, some aberrometers require the pupil
diameter to be large enough for a measurement. If the pupil diameter is
not large enough in low light, then that person may not be a candidate.

Q: What percentage of candidates could have a wavefront-guided procedure?

A: Approximately 95 percent of potential LASIK patients are great candidates for a wavefront-guided procedure.

Q: Do you have any other thoughts for someone who might want a wavefront-guided or other procedure?

A:
A well-performed optimized procedure and a well-performed
wavefront-guided procedure may have very similar results when viewing a
simple eye chart.

The
differences between the two would be most apparent for other aspects of
vision, particularly tasks that require a high visual demand, such as
night driving. This is where the superior visual results of the
wavefront-guided procedure really shine.

Published results of wavefront-guided procedures have reported improved contrast sensitivity and fewer higher-order aberrations compared with a standard treatment.

Some
examples of how this would help in more practical terms would be an
improved ability to read a road sign in a fog or more easily recognizing
a face in a crowd. The wavefront-guided procedure results in a higher
quality of vision.

If someone is interested in the highest quality
of vision after LASIK — and I don't know who wouldn't be — then I would
recommend a wavefront-guided treatment. As a powerful testimony to
this, it was the superior results of wavefront-guided procedures that
led to the approval of LASIK for military fighter pilots and NASA
astronauts.

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